Support substrate for transfer of semiconductor devices

ABSTRACT

An apparatus for transferring a semiconductor die from a wafer tape to a product substrate. The apparatus includes a wafer frame configured to secure the wafer tape and a support frame configured to secure a support substrate. The support substrate includes a plurality of holes and secures the product substrate. The apparatus further includes an actuator to transfer the semiconductor die to a transfer location on the product substrate.

CROSS REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 15/409,409, filed Jan. 18, 2017, entitled “FlexibleSupport Substrate for Transfer of Semiconductor Devices,” the entiretyof which is herein incorporated by reference. This application alsoincorporates by reference, in its entirety, U.S. patent application Ser.No. 14/939,896, filed on Nov. 12, 2015, entitled “Apparatus for Transferof Semiconductor Devices,” which is now patented as U.S. Pat. No.9,633,883.

BACKGROUND

Semiconductor devices are electrical components that utilizesemiconductor material, such as silicon, germanium, gallium arsenide,and the like. Semiconductor devices are typically manufactured as singlediscrete devices or as integrated circuits (ICs). Examples of singlediscrete devices include electrically-actuatable elements such aslight-emitting diodes (LEDs), diodes, transistors, resistors,capacitors, fuses, etc.

The fabrication of semiconductor devices typically involves an intricatemanufacturing process with a myriad of steps. The end-product of thefabrication is a “packaged” semiconductor device. The “packaged”modifier refers to the enclosure and protective features built into thefinal product as well as the interface that enables the device in thepackage to be incorporated into a product circuit.

The conventional fabrication process for semiconductor devices startswith handling a semiconductor wafer. The wafer is diced into a multitudeof “unpackaged” semiconductor devices. The “unpackaged” modifier refersto an unenclosed semiconductor device without protective features.Herein, unpackaged semiconductor devices may be called semiconductordevice die, or just “die” for simplicity. A single semiconductor wafermay be diced to create die of various sizes, so as to form upwards ofmore than 100,000 or even 1,000,000 die from the semiconductor wafer(depending on the starting size of the semiconductor), and each die hasa certain quality. The unpackaged die are then “packaged” via aconventional fabrication process discussed briefly below. The actionsbetween the wafer handling and the packaging may be referred to as “diepreparation.”

In some instances, the die preparation may include sorting the die via a“pick and place process,” whereby diced die are individually picked upand sorted into bins. The sorting may be based on the forward voltagecapacity of the die, the average power of the die, and/or the wavelengthof the die.

Typically, the packaging involves mounting a die onto a plastic orceramic package (e.g., mold or enclosure). Packaging may also includeconnecting the die contacts to pins/wires forinterfacing/interconnecting with product circuitry. The packaging of thesemiconductor device is typically completed by sealing the die toprotect it from the environment (e.g., dust).

After packaging, a product manufacturer then places packagedsemiconductor devices in product circuitry. Due to the packaging, thedevices are ready to be “plugged in” to the circuit assembly of theproduct being manufactured. Additionally, while the packaging of thedevices protects them from elements that might degrade or destroy thedevices, the packaged devices are inherently larger (e.g., in somecases, around 10 times the thickness and 10 times the area, resulting in100 times the volume) than the die found inside the package. Thus, theresulting circuit assembly cannot be any thinner than the packaging ofthe semiconductor devices.

When mounting an unpackaged die onto product circuitry, significantforces may be exerted on the body of the unpackaged die. Due to theproperties and characteristics of unpackaged die or the package beingused, these exerted forces may cause damage to the unpackaged die beingtransferred, the circuit substrate, and/or contacts (circuit trace)electrically linking the unpackaged die. Such damage may ultimately leadto failure of the product.

BRIEF DESCRIPTION OF THE DRAWINGS

The Detailed Description is set forth with reference to the accompanyingfigures. In the figures, the left-most digit(s) of a reference numberidentifies the figure in which the reference number first appears. Theuse of the same reference numbers in different figures indicates similaror identical items. Furthermore, the drawings may be considered asproviding an approximate depiction of the relative sizes of theindividual components within individual figures. However, the drawingsare not to scale, and the relative sizes of the individual components,both within individual figures and between the different figures, mayvary from what is depicted. In particular, some of the figures maydepict components as a certain size or shape, while other figures maydepict the same components on a larger scale or differently shaped forthe sake of clarity.

FIG. 1 illustrates an isometric view of an embodiment of a transferapparatus.

FIG. 2A represents a schematic view of an embodiment of a transferapparatus in a pre-transfer position.

FIG. 2B represents a schematic view of an embodiment of a transferapparatus in a transfer position.

FIG. 2C illustrates a schematic view of another embodiment of a transferapparatus in a pre-transfer position.

FIG. 3 illustrates a plan view of an embodiment of a product substratehaving a circuit trace with semiconductor die thereon.

FIG. 4 illustrates an exploded perspective view of an embodiment of asupport substrate and a product substrate, according to an embodiment ofthe instant application.

FIG. 5 illustrates an exploded perspective view of an embodiment of asupport substrate and a product substrate, according to an embodiment ofthe instant application.

FIG. 6 illustrates a method of a die transfer process according to anembodiment of the instant application.

DETAILED DESCRIPTION

This disclosure is directed generally to a machine that directlytransfers and affixes semiconductor device die to a circuit and to theprocess for achieving the same, as well as to the circuit having dieaffixed thereto (as the output product). In some instances, the machinefunctions to transfer unpackaged die directly from a substrate such as a“wafer tape” to a product substrate, such as a circuit substrate. Theproduct substrate may be secured to or otherwise supported by a flexiblesupport substrate. The flexible support substrate may serve to dampen,through deflection or other means, forces associated with the transferprocess. Since the direct transfer of unpackaged die (hereinafter “die”)may significantly reduce the thickness of an end product compared to asimilar product produced by conventional means using conventionalpackaged die, as well as the amount of time and/or cost to manufacturethe product substrate, it is advantageous to make the transfer processrun as smoothly as is possible.

For the purpose of this description, the term “substrate” refers to anysubstance on which, or to which, a process or action occurs. Further,the term “product” refers to the desired output from a process oraction, regardless of the state of completion. Thus, a product substraterefers to any substance on which, or to which, a process or action iscaused to occur for a desired output. Likewise, a support substraterefers to any suitable substance for supporting a product substrate, asdiscussed further herein below.

In an embodiment, the machine may secure a support substrate. Thesupport substrate may be configured to assist in the transfer process,for instance, through dampening forces exerted by the machine during thetransfer of die. Through dampening these forces, the support substratemay reduce stress, strain, and/or other forces being imparted to the dieand/or product substrate.

Prior to transferring a die, a product substrate is secured to thesupport substrate. The product substrate is configured to receive die,such as LEDs, being transferred from the wafer tape, for example. Toensure an accurate die transfer, the product substrate is adequatelysecured to support substrate such that product substrate does notreposition or shift during the process of transferring die to productsubstrate.

The product substrate may be secured to the support substrate via anysuitable means. For example, the product substrate may be secured viaadhesive means, such as a resin or glue, tape, or a releasable tackymaterial. Additionally, and/or alternatively, the product substrate maybe secured via a system of holes in the support substrate that alignwith respective protrusions on the product substrate to hold the productsubstrate in place. Moreover, the product substrate may be secured usingmechanical fasteners.

In general, the unpackaged die to be transferred are very small andthin. For example, a die may be about 50 microns thick or less. Due tothe relatively small size of the die, the machine includes componentsthat function to precisely align both the wafer tape carrying the dieand the product substrate, so as to ensure accurate placement and/oravoid product material waste. This alignment generally also includesaligning the die with a circuit trace on the product substrate. Due tothe interaction between the product substrate and the support substrate,as referred to herein, alignment of the product substrate isaccomplished by maneuvering or positioning the support substrate whensupporting the product substrate.

In an embodiment, the components that align the product substrate andthe die on the wafer tape may include a set of frames in which the wafertape and the support substrate are secured respectively and conveyedindividually to a position of alignment such that a specific die on thewafer tape is transferred to a specific spot on the product substrate.That is, as alluded to previously, the product substrate may be alignedinto position through movement of the frame holding the supportsubstrate.

The frame that conveys the support substrate may travel in variousdirections, including horizontal directions and/or vertical directions,or even directions that would permit transfer to a curved surface. Forinstance, the frame may rotate. The frame that conveys the wafer tapemay also travel in various directions. A system of gears, tracks,motors, and/or other elements may be used to secure and convey theframes carrying the support substrate and the wafer tape respectively toalign the product substrate with the wafer tape in order to place a dieon the correct position of the product substrate. Each frame system mayalso be moved to an extraction position in order to facilitateextraction of the wafer tape, the support substrate, and/or the productsubstrate upon completion of the transfer process.

The machine may further include a transfer mechanism for transferringthe die directly from the wafer tape to the product substrate without“packaging” the die. The transfer mechanism may be disposed verticallyabove the wafer tape so as to press down on the die via the wafer tapetoward the product substrate. The process of pressing down on the diemay cause the die to peel off the wafer tape, starting at the sides ofthe die until the die separate from the wafer tape to be attached to theproduct substrate. That is, by reducing the adhesion force between thedie and the wafer tape, and increasing the adhesion force between thedie and the product substrate, the die may be transferred to the productsubstrate.

In some embodiments, the transfer mechanism may include a transferelement. In an embodiment, the transfer element may include an elongatedrod, such as a pin or needle that may be cyclically actuated against thewafer tape to push the wafer tape from a top side. The transfer elementhead may be sized so as to be no wider than a width of the die beingtransferred. Alternatively, the width of the transfer element head maybe wider than a width of a die being transferred. Further, the transferelement may be sized to transfer multiple die at the same time or duringa single press or cycle thereof. When the end of the transfer elementcontacts the wafer tape, the wafer tape may experience a localdeflection at the area between the die and the wafer tape. Inasmuch asthe deflection is highly localized and rapidly performed, the portion ofthe wafer tape that does not receive pressure from the transfer elementmay begin to flex away from the surface of the die. This partialseparation may thus cause the die to lose sufficient contact with thewafer tape, so as to release from the wafer tape and transfer to theproduct substrate. Moreover, in some instances, the deflection of thewafer tape may be so minimal, as to maintain an entirety of the surfacearea of the die in contact with the wafer tape, while still causing theopposing surface of the die to extend beyond a plane of extension of thecorresponding surface of the adjacent die, thereby allowing the targetdie to be transferred by connection to the circuit trace and being fixedthereto, while avoiding an unintentional transfer of the adjacent die.Note, for the purposes of simplicity, the transfer element may bereferred to hereinafter as “the needle.”

As previously mentioned, the support substrate is flexible and supportsthe product substrate such that forces exerted by the transfer mechanismagainst the die and/or the product substrate during a transfer processmay be dampened. Thus, when die are transferred to the productsubstrate, the support substrate may deflect, in response to the pressof the transfer mechanism, such that the effect of the transfer force isminimized on the die and/or the product substrate. Therefore, the effectof dampening by the support substrate may prevent the die(s) and/orproduct substrate from breaking or being otherwise damaged.

The machine may further include a fixing mechanism for affixing theseparated die to the product substrate. In some instances, and asmentioned, the product substrate may have thereon a circuit trace towhich the die are transferred and affixed. The fixing mechanism mayinclude a device that emits energy, such as a laser, to melt/soften thematerial of the circuit trace on the product substrate. Additionally,the energy-emitting device may melt/soften material of the productsubstrate to form a further bond between the product substrate and thedie.

Considering the effect of the energy-emitting device used, a particularsupport substrate may be chosen so as to avoid being melted or becomingdeformed during a transfer. For example, when using a laser as theenergy-emitting device 236, the chosen material of the support substratemay have characteristics that permit a particular wavelength of lightused in the laser to pass therethrough, such that the energy appliedfrom the laser does not affect the support substrate. More particularly,a support substrate of a predetermined material may be unaffected by acertain wavelength of light that is used to melt, soften, or otherwiseprepare circuit trace and/or product substrate for receiving die.However, in other embodiments, the wavelength may be chosen to have aneffect on all or some of the circuit trace, product substrate, andsupport substrate. For instance, in an embodiment, the product substratemay be secured to the support substrate though the energy-emittingdevice.

In another example embodiment, the support substrate may include aplurality of holes therethrough that provide an opening for the energyemitted from the fixing mechanism to pass through the support substrateto directly reach the product substrate. The support substrate may havea predetermined pattern of hole locations according to the circuit tracepattern and/or die placement on the product substrate. Moreover, avariety of support substrates may be created to form templates forvarious product substrates having different die placements.

First Example Embodiment of a Direct Transfer Apparatus

FIG. 1 illustrates an embodiment of an apparatus 100 that may be used todirectly transfer unpackaged semiconductor components (or “die”) from awafer tape to a product substrate. The wafer tape may also be referredto herein as the semiconductor device die substrate, or simply a diesubstrate. Apparatus 100 may include a support substrate conveyancemechanism 102 and a wafer tape conveyance mechanism 104. Located on thesupport substrate, a product substrate may be positioned to receive thedie being transferred from the wafer tape. Each of support substrateconveyance mechanism 102 and wafer tape conveyance mechanism 104 mayinclude a movable frame system to desired alignment positions withrespect to each other.

Apparatus 100 may further include a transfer mechanism 106, which, asshown, may be disposed vertically above wafer tape conveyance mechanism104. In some instances, transfer mechanism 106 may be positioned so asto nearly contact the wafer substrate. Additionally, apparatus 100 mayinclude a fixing mechanism 108. Fixing mechanism 108 may be disposedvertically beneath support substrate conveyance mechanism 102 inalignment with transfer mechanism 106, at a transfer position fortransferring a die to the product substrate.

Furthermore, apparatus 100 may be communicatively coupled to a computingdevice 110. Computing device 110 is configured to receive informationand data useful in the transfer process of directly transferring diefrom a wafer tape in wafer tape conveyance mechanism 104 using thetransfer mechanism 106 on to a product substrate supported by thesupport substrate conveyance mechanism 102, whereat the die may be fixedupon the product substrate via actuation of a laser or otherenergy-emitting device (fixing mechanism 108). Computing device 110 mayalso serve as a receiver, compiler, organizer, and controller of databeing relayed to and from each of wafer tape conveyance mechanism 104,support substrate conveyance mechanism 102, transfer mechanism 106, andfixing mechanism 108. Thus, computing device 110 may cause the variouscomponents of apparatus 100 to perform programmed functions. Computingdevice 110 may further receive directed information from a user of theapparatus 100.

Inasmuch as FIGS. 2A and 2B depict different stages of the transferoperation, while referring to the same elements and features ofapparatus 200(1), the following discussion of specific features mayrefer interchangeably to either or both FIGS. 2A and 2B, except whereexplicitly indicated. In addition, some of the features from FIGS. 2Aand 2B will be discussed later herein with reference to featuressimilarly found in FIG. 2C.

In particular, FIGS. 2A and 2B illustrate an embodiment of an apparatus200(1), including a support substrate conveyance mechanism 202, a wafertape conveyance mechanism 204, a transfer mechanism 206, and a fixingmechanism 208. Support substrate conveyance mechanism 202 may bedisposed adjacent to wafer tape conveyance mechanism 204. For example,as illustrated, support substrate conveyance mechanism 202 may extend ina substantially horizontal direction and may be disposed verticallybeneath wafer tape conveyance mechanism 204 so as to take advantage ofany effect that gravity may have in the transfer process. Alternatively,support substrate conveyance mechanism 202 may be oriented so as toextend transversely to a horizontal plane.

During a transfer operation, conveyance mechanisms 202, 204 may bepositioned such that a space between a surface of a product substrate,which is carried by support substrate conveyance mechanism 202, and asurface of a wafer tape, which is carried by wafer tape conveyancemechanism 204, may be more or less than 1 mm. This space may varydepending on other aspects of apparatus 200(1), including the amount ofdeflection that occurs by components during the transfer process, asdescribed herein below. In an embodiment, the respective opposingsurfaces of the wafer tape and the product substrate may be the mostprominent structures in comparison to the supporting structures ofconveyance mechanisms 202, 204. That is, in order to avoid a collisionbetween components of the machine and products thereon, which might becaused by movable parts (e.g., conveyance mechanisms 202, 204), adistance between the respective surfaces of the wafer tape and productsubstrate may be less than a distance between any other opposingstructural components.

As depicted, and in some instances, transfer mechanism 206 may bedisposed vertically above wafer tape conveyance mechanism 204, andfixing mechanism 208 may be disposed vertically beneath supportsubstrate conveyance mechanism 202. It is contemplated that in someembodiments, one or both of transfer mechanism 206 and fixing mechanism208 may be oriented with respect to each other in a manner other thanthat illustrated in FIGS. 2A and 2B. For instance, transfer mechanism206 may be disposed so as to extend at an acute angle with respect to ahorizontal plane. In another embodiment, fixing mechanism 208 may beoriented to emit energy during the transfer process from the samedirection of actuation as transfer mechanism 206, or alternatively, fromany orientation and position from which fixing mechanism 208 is able toparticipate in the transfer process.

Support substrate conveyance mechanism 202 may be used to secure asupport substrate 210. Herein, the term “support substrate” may include,but is not limited to: a polymer substrate, where the polymer, whethertranslucent or otherwise, may be selected from any suitable polymers,including, but not limited to, silicone, acrylic, polyester,polycarbonate, polyimide, etc.; a cloth material of cotton, nylon,rayon, leather, etc.; or any other surface suitable for receiving andsupporting a product substrate. The choice of material of supportsubstrate 210 may also include materials that are durable, resilient,and flexible.

Support substrate 210 may be capable of withstanding repetitive andcyclic die transfer processes. In addition, support substrate 210 may beselected according to properties and/or characteristics of the productsubstrate and/or the die being used. That is, the support substrate maybe chosen to achieve desired dampening during the transfer process.Furthermore, while varying product substrates may be used in conjunctionwith apparatus 200(1), support substrate 210 may be sufficientlyversatile such that a single support substrate may be implemented withvarious die(s) and/or product substrates. That is, support substrate 210may be selected to be universal with varying product substrates and/ordie or may be selected according to each product substrate and/or diebeing used.

Support substrate 210 is configured to receive, support, and secureproduct substrate 248. Herein, the term “product substrate” may include,but is not limited to: a wafer tape (for example, to presort the die andcreate sorted die sheets for future use); a paper or polymer substrateformed as a sheet or other non-planar shape, where thepolymer—translucent or otherwise—may be selected from any suitablepolymers, including, but not limited to: silicone, acrylic, polyester,polycarbonate, polyimide, etc.; a circuit board (such as a printedcircuit board (PCB)); a string or thread circuit, which may include apair of conductive wires or “threads” extending in parallel; and a clothmaterial of: cotton, nylon, rayon, leather, etc. The choice of materialof product substrate 248 may include durable materials, flexiblematerials, rigid materials, and other materials with which the transferprocess is successful and which maintain suitability for the end use ofproduct substrate 248. Product substrate 248 may also be formed solelyor at least partially of conductive material such that product substrate248 may act as a conductive circuit for forming a product. Productsubstrate 248 may be thinner, thicker, or the same thickness as supportsubstrate 210. The potential types of product substrate may furtherinclude items, such as glass bottles, vehicle windows, or sheets ofglass.

Product substrate 248 may be secured to support substrate 210 through aplurality of methods so as to assist in the alignment aspect of thetransfer process. Product substrate 248 may be secured to supportsubstrate 210 during the transfer process via adhesive means, such as atape or glue. Other means of securing product substrate 248 may include:static friction, suction, fusion, mechanical means, etc. Additionally,as mentioned previously, and in an embodiment, the product substrate maybe secured via a system of holes in the support substrate that alignwith protrusions on the product substrate. Furthermore, productsubstrate 248 may be either permanently or temporarily affixed tosupport substrate 210. Inasmuch as product substrate is eitherpermanently or temporarily affixed, support substrate is permitted todampen forces associated with the transfer process.

When permanently affixed to the support substrate, support substrate mayreinforce product substrate, encapsulate product substrate so as toprotect the product substrate and/or die, or become part of a productcircuit. In cases where permanently affixed, as will be discussedherein, after transfer of the die(s), support substrate and productsubstrate may be removed together. Thereafter, a subsequent supportsubstrate may be placed in the support substrate conveyance mechanismprior to the die transfer process on a subsequent product substrate.

Alternatively, in an embodiment where product substrate is temporarilyattached to support substrate, after transfer of the die, productsubstrate may be removed from support substrate. Such removal may occurwhile support substrate is still secured in the machine or after supportsubstrate and product substrate are removed from the machine together.To assist removal, conveyance mechanism(s) 202 and/or 204 may bemaneuvered. Separation of product substrate from support substrate mayinvolve whatever means required. Once removed and separated, asubsequent product substrate may be secured to the support substrate foradditional transfer processes. That is, as mentioned previously, supportsubstrate may be reusable and configured to support various productsubstrates.

Note that while product substrate 248 is shown as being elevated abovean opposing surface of support substrate 210, separated by a gap, thedepicted gap is only for illustration purposes to illustrate thealignment and positioning of support substrate 210 and product substrate248 as distinct components. That is, during the transfer process,opposing surfaces of support substrate 210 and product substrate 248 maybe flush with each other. Additionally, and/or alternatively, in someinstances, the product substrate may be secured to the support substratevia one or more points of contact, such that a gap (air gap), may existbetween a portion of the support substrate and the product substrate(not shown).

As previously mentioned, support substrate 210 may be configured tosupport product substrate 248 during and when product substrate 248receives die 220. More particularly, it is contemplated that productsubstrate 248 and/or die 220 may be susceptible to damage during thetransfer process. Accordingly, a suitable support substrate 210 may beselected based on the product substrate and/or die being transferred.Such support substrate may serve to dampen the force of the transfer topermit die 220 to be transferred onto product substrate 248 without anyor significant damage.

For instance, in an embodiment where product substrate 248 and/or die220 is fragile or rigid (e.g. given the “unpackaged” nature of the die),a flexible support substrate may be selected. When transferring thedie(s), the flexible support substrate may allow downward deflection soas to dampen the forces associated with the transfer process. In turn,the flexible support substrate may prevent these forces from beingintroduced to die 220 and/or product substrate 248.

In another embodiment, support substrate 210 may be chosen to reinforcea thin product substrate that may otherwise bend, deform, or puncturewithout reinforcement during the transfer process. Correspondingly, inboth above instances, which are included for illustrations only and donot present limiting examples, support substrate 210 may help maintainthe integrity and viability of die 220 and/or product substrate 248.

In an embodiment as depicted in FIGS. 2A and 2B, product substrate 248may include a circuit trace 212 disposed thereon. Circuit trace 212, asdepicted, may include a pair of adjacent trace lines spaced apart by atrace spacing, or gap so as to accommodate a distance between electricalcontact terminals (not shown) on the die being transferred. Thus, thetrace spacing, or gap between the adjacent trace lines of circuit trace212 may be sized according to the size of the die being transferred toensure proper connectivity and subsequent activation of the die. Forinstance, circuit trace 212 may have a trace spacing, or gap rangingfrom about 75 to 200 microns, about 100 to 175 microns, or about 125 to150 microns. However, while only one conductive trace 212 is shown, itis contemplated that product substrate 248 may have a plurality ofconductive traces 212 for receiving multiple die. In turn, transfermechanism 206 may be capable of transferring die 220 on circuit trace212 having a multiple designs, configurations, or patterns.

Circuit trace 212 may be formed from a conductive ink disposed viascreen printing, inkjet printing, laser printing, manual printing, orother printing means. Further, circuit trace 212 may be pre-cured andsemi-dry or dry to provide additional stability, while still beingactivatable for die conductivity purposes. A wet conductive ink may alsobe used to form circuit trace 212, or a combination of wet and dry inkmay be used for circuit trace 212. Alternatively, or additionally,circuit trace 212 may be pre-formed as a wire trace, or photo-etched, orfrom molten material formed into a circuit pattern and subsequentlyadhered, embedded, or otherwise secured to product substrate 248.

The material of circuit trace 212 may include, but is not limited to,silver, copper, gold, carbon, conductive polymers, etc. In someinstances, circuit trace 212 may include a silver-coated copperparticle. A thickness of circuit trace 212 may vary depending on thetype of material used, the intended function and appropriate strength orflexibility to achieve that function, the energy capacity, the size ofthe LED, etc. For example, a thickness of the circuit trace may rangefrom about 5 microns to 20 microns, from about 7 microns to 15 microns,or from about 10 microns to 12 microns.

Accordingly, in a non-limiting example, product substrate 248 may be aflexible, translucent polyester sheet having a desired circuit patternscreen printed thereon using a silver-based conductive ink material toform the circuit trace 212.

Support substrate conveyance mechanism 202 may include a supportsubstrate conveyor frame 214 for securing a support substrate holderframe 216. The structure of support substrate holder frame 216 may varysignificantly depending on the type and properties (e.g., shape, size,elasticity, etc.) of support substrate 210 and/or product substrate 248being used. In an embodiment, insofar as support substrate 210 and/orproduct substrate 248 may include a flexible material, support substrate210 may be held under tension in support substrate holder frame 216, soas to create a more rigid surface upon which a transfer process,discussed herein below, is performed. Product substrate 248 may becoupled to support substrate 210 either before or after supportsubstrate 210 is secured in frame 216.

In the above instance, the rigidity created by the tension in supportsubstrate 210 may increase the placement accuracy when transferringcomponents, such as die 220 on product substrate 248. For example, in anembodiment, using a durable and rigid material for the productsubstrate, support substrate 210 may naturally provide a firm surface toassist in placement accuracy. In contrast, when support substrate 210 ispermitted to sag, wrinkles and/or other discontinuities may form insupport substrate 210 and/or product substrate 248 so as to interferewith the pre-set pattern of circuit trace 212, to the extent that thetransfer operation may be unsuccessful. However, despite supportsubstrate 210 being held under tension within frame 216, supportsubstrate 210 may still dampen forces associated with the transferprocess.

While the means of securing support substrate 210 may vary greatly, FIG.2A illustrates an embodiment of support substrate holder frame 216including a first portion 216 a having a concave shape and a secondportion 216 b having a convex counter shape that corresponds in shape tothe concave shape. In the depicted example, tension is created forsupport substrate 210 by inserting an outer perimeter of supportsubstrate 210 between first portion 216 a and second portion 216 b tothereby clamp support substrate 210 tightly.

Insofar as frame 216 may damage a substrate through clamping, byincluding support substrate 210, support substrate 210 may prevent suchdamage from being introduced to product substrate 248. That is, damagemay be avoided to product substrate 248 due to the tensioning of supportsubstrate 210 as secured between first and second portions 216 a, 216 b.

Support substrate conveyor frame 214 may be conveyed in at least threedirections—two directions in the horizontal plane and one direction inthe vertical plane. However, conveyance may also occur about an axis.Conveyance may be accomplished via a system of motors, rails, and gears(not shown). As such, support substrate holder frame 216 may be conveyedto and held in a specific position as directed and/or programmed andcontrolled by a user of apparatus 200(1).

Wafer tape conveyance mechanism 204 may be implemented to secure a wafertape 218 having die 220 (i.e., semiconductor device die) thereon. Wafertape 218 may be conveyed in multiple directions to the specific transferpositions for the transfer operation via a wafer tape conveyor frame222. Similar to support substrate conveyor frame 214, wafer tapeconveyor frame 222 may include a system of motors, rails, and gears(none of which are shown).

As mentioned previously, the die(s) 220 for transfer may be extremelysmall. Accordingly, there is a need to prevent damage to the die duringthe transfer process. In an embodiment, the height of die 220 may rangefrom 12.5 to 200 microns, or from 25 to 100 microns, or from 50 to 80microns. Due to the micro size of die 220, when wafer tape 218 has beenconveyed to the appropriate transfer position, a gap spacing betweenwafer tape 218 and product substrate 248 may range from about 0.25 mm to1.50 mm, or about 0.50 mm to 1.25 mm, or about 0.75 mm to 1.00 mm, forinstance. A minimum gap spacing may depend on factors including: athickness of die(s) 220 being transferred, a stiffness of wafer tape 218involved, an amount of deflection of wafer tape 218 needed to provideadequate capture and release of die 220, a proximity of the adjacent die220 on wafer tape 218, etc. As the distance between wafer tape 218 andproduct substrate 248 decreases, a speed of the transfer operation mayalso decrease due to the reduced cycle time (discussed further herein)of the transfer operation. Such a decrease in the duration of a transferoperation may therefore increase a rate of die transfers. For instance,in a non-limiting example, the die transfer rate may range from about6-20 die placed per second.

In some instances, materials used for the die may include, but is notlimited to, silicon carbide, gallium nitride, a coated silicon oxide,etc. Furthermore, sapphire or silicon may be used as well. Additionally,as indicated above, a “die” may be representative herein of anelectrically actuatable element generally.

Furthermore, wafer tape conveyor frame 222 may secure a wafer tapeholder frame 224, which may stretch and hold wafer tape 218 undertension. As illustrated in FIG. 2A, wafer tape 218 may be secured inwafer tape holder frame 224 via clamping a perimeter of wafer tape 218between adjacent components of wafer holder frame 224. Such clamping mayassist in maintaining the tension and stretched characteristic of wafertape 218, thereby increasing the success rate and accurate placement ofdie 220 during the transfer operation. In view of the varying propertiesof different types, brands, and qualities of wafer tapes available, aparticular wafer tape may be selected for use based on an ability toconsistently remain at a desired tension during a transfer process. Insome instances, the actuation performance profile of the transferelement may change depending on the tension of wafer tape 218 and/or toprevent damage to die 220.

The material used for wafer tape 218 may include a material havingelastic properties, such as a rubber or silicone, for example.Furthermore, inasmuch as temperature of the environment during transferand wafer tape 218 itself may contribute to potential damage to wafertape 218 during the transfer process, a material having properties thatare resistant to temperature fluctuation may be advantageous.Additionally, in some instances, wafer tape 218 may be stretchedslightly so as to create a separation or gap between individual die 220to assist in the transfer operation. A surface of wafer tape 218 mayinclude a sticky or adhesive substance via which die 220 may beremovably adhered to wafer tape 218.

Wafer tape 218 may include die 220 that were individually cut from asolid semiconductor wafer and then placed onto wafer tape 218 to securedie 220. In such a situation, the die may be pre-sorted and explicitlyorganized on wafer tape 218, in order, for example, to assist in thetransfer operation. In particular, die 220 may be arranged sequentiallyas to the expected order of transfer to product substrate 248. Suchpre-arrangement of die 220 on wafer tape 218 may reduce the amount oftravel that would otherwise occur between conveyance mechanisms 202,204. Additionally, or alternatively, die 220 on wafer tape 218 may havebeen pre-sorted to include only die 220 having substantially equivalentperformance properties. In this case, efficiency of the supply chain maybe increased and thus, travel time of wafer tape conveyance mechanism204 may be reduced.

In some embodiments, wafer tape 218 may include die that are notpre-sorted, but rather are formed by simply cutting a semiconductordirectly on wafer tape, and then leaving the die on the wafer tapewithout “picking and placing” to sort the die depending on therespective performance quality of the die. In such a situation, the dieon the wafer tape may be mapped to describe the exact relative locationsof the different quality die. Therefore, in some instances, it may beunnecessary to use wafer tape having pre-sorted die. In such a case, theamount of time and travel for wafer tape conveyance mechanism 204 tomove between particular die for each sequential transfer operation mayincrease. This may be caused in part by the varying quality of the diedispersed within the area of the semiconductor, which means that a dieof a specific quality for the next transfer operation may not beimmediately adjacent to the previously transferred die. Thus, wafer tapeconveyance mechanism 204 may move wafer tape 218 further to align anappropriate die of a specific quality for transfer than would benecessary for a wafer tape 218 containing die of substantiallyequivalent quality.

In further regard to die 220 on wafer tape 218, in some instances, adata map of die 220 may be provided with wafer tape 218. The data mapmay include a digital file providing information that describes thespecific quality and location of each die 220 on wafer tape 218. Thedata map file may be input into a processing system in communicationwith apparatus 200(1), whereby apparatus 200(1) may becontrolled/programmed to seek the correct die 220 on wafer tape 218 fortransfer to product substrate 248.

A transfer operation is performed, in part, via transfer mechanism 206,which is a die separation device for assisting in separation of die 220from wafer tape 218. The actuation of transfer mechanism 206 may causeone or more die 220 to be released from wafer tape 218 and to becaptured by product substrate 248. As discussed above, in an embodiment,transfer mechanism 206 may operate by pressing a transfer element, suchas elongated rod, a pin, or a needle 226 into a top surface of wafertape 218 against die 220. Needle 226 may be connected to a needleactuator 228 that may include a motor connected to needle 226 to driveneedle 226 toward wafer tape 218 at predetermined/programmed times.

In view of the function of needle 226, needle 226 may include a materialthat is sufficiently durable to withstand repetitive, rapid, minorimpacts while minimizing potential harm to die 220 upon impact and asdie 220 are pushed into contact with product substrate 248. For example,needle 226 may include a metal, a ceramic, a plastic, etc. Additionally,a tip of needle 226 may have a particular shape profile, such as beingrounded or chamfered, which may affect the ability of the needle tofunction repetitively without frequently breaking either the tip ordamaging wafer tape 218 or die 220.

In a transfer operation, needle 226 may be aligned with a particular die220, as depicted in FIG. 2A, and needle actuator 228 may move needle 226to push against an adjacent side of wafer tape 218 at a position inwhich die 220 is aligned on the opposing side of wafer tape 218, asdepicted in FIG. 2B. The pressure from needle 226 may cause wafer tape218 to deflect so as to extend die 220 toward a position closer toproduct substrate 248 than adjacent die 220, which are not beingtransferred. As indicated above, the amount of deflection may varydepending on several factors, such as the thickness of the die andcircuit trace (e.g. a thinner circuit trace may require the wafer tapeto deflect farther downward). For example, where die 220 is about 50microns thick and circuit trace 212 is about 10 microns thick, an amountof deflection of wafer tape 218 may be about 75 microns. Thus, die 220may be pressed via needle 226 toward product substrate 248 to the extentthat the electrical contact terminals (not shown) of die 220 are able tobond with circuit trace 212, at which point, the transfer operationproceeds to completion and die 220 is released from wafer tape 218.During such operation, support substrate 210 may flex so as to dampenforces created by pressing the die 220 into contact with the contactterminals.

In addition, while the transfer process described above discusses thetransfer with respect to a particular die, wafer tape 218 and needle 226may be configured to transfer multiple die during a single transferoperation. However, to the extent that the transfer process may includea rapidly repeated set of steps including a cyclical actuation of needle226 pressing upon die 220, a method of the process is described indetail herein below with respect to FIG. 6.

Turning attention back to FIGS. 2A and 2B, in an embodiment, transfermechanism 206 may further include a needle retraction support 230, (alsoknown as a pepper pot). In an embodiment, support 230 may include astructure having a hollowed space whereby needle 226 may be accommodatedby passing into the space via an opening 232 in a first end of support230. Support 230 may further include at least one opening 234 on asecond opposing end of support 230. Moreover, support 230 may includemultiple perforations near opening 234. The at least one opening 234 maybe sized with respect to a diameter of needle 226 to accommodate passageof needle 226 therethrough so as to press on wafer tape 218 during thetransfer process. In an embodiment, support 230 may be disposed adjacentto the upper surface of wafer tape 218. As such, when needle 226 isretracted from pressing on wafer tape 218 during a transfer operation, abase surface of support 230 (having the at least one opening 234therein) may come into contact with the upper surface of wafer tape 218,thereby preventing upward deflection of wafer tape 218. This upwarddeflection may be caused in the event where needle 226 pierces at leastpartially into wafer tape 218, and while retracting, the wafer tape isstuck to the tip of needle 226. Thus, support 230 may reduce the time ittakes to move to the transfer process to the next die 220.

When die 220 are transferred according to a data map, support 230 maymaintain the accuracy when placing die 220 as support 230 may preventdeflection of deformation of support substrate 210 and/or productsubstrate 248. A wall perimeter shape of support 230 may be cylindricalor any other shape that may be accommodated in apparatus 200(1).Accordingly, support 230 may be disposed between needle 226 and an uppersurface of wafer tape 218.

With respect to the effect of temperature on the integrity of wafer tape218, it is contemplated that a temperature of support 230 may beadjusted so as to regulate the temperature of needle 226 and wafer tape218, at least near the point of the transfer operation. Accordingly, thetemperature of support 230 may be heated or cooled, and a material ofsupport 230 may be selected to maximize thermal conductivity. Forexample, support 230 may be formed of aluminum, or another relativelyhigh thermal conductivity metal or comparable material, whereby thetemperature may be regulated to maintain consistent results of thetransfer operations. In some instances, air may be circulated withinsupport 230 to assist in regulating the temperature of a local portionof wafer tape 218. Additionally, or alternatively, a fiber optic cable230 a may be inserted into needle retraction support 230, and mayfurther be against needle 226 to assist in temperature regulation ofwafer tape 218 and/or needle 226.

As indicated above, fixing mechanism 208 may assist in affixing die 220to the circuit trace 212 on a surface of product substrate 248. FIG. 2Billustrates apparatus 200(1) in a transfer stage, where die 220 ispushed/pressed against circuit trace 212 on product substrate 248. In anembodiment, fixing mechanism 208 may include an energy-emitting device236 including, but not limited to: a laser; electromagnetic radiation;pressure vibration; ultrasonic welding; etc. In some instances, the useof pressure vibration for the energy-emitting device 236 may function byemitting a vibratory energy force so as to cause disruption of themolecules within circuit trace 212 against those of the electricalcontact terminals so as to form a bond via the vibratory pressure.

In a non-limiting example, as depicted in FIG. 2B, a laser may beimplemented as the energy-emitting device 236. During a transferoperation, laser 236 may be activated to emit a specific wavelength andintensity of light energy directed at die(s) 220 being transferred. Thewavelength of the light of laser 236 may be selected specifically basedon the absorption of that wavelength of light with respect to thematerial of circuit trace 212 without significantly affecting thematerial of support substrate 210 and/or product substrate 248. Forexample, in an embodiment, a laser having an operational wavelength of808 nm, and operating at 5 W may be readily absorbed by silver of thecircuit trace, but not by a polymer used in either the support substrateor the product substrate. As such, light from the laser may pass throughsupport substrate 210 and product substrate 248 and affect the silver ofcircuit trace 212. Alternatively, the wavelength of light may beselected based on the absorption of that wavelength of light withrespect to circuit trace 212 and material of product substrate 248,while not affecting support substrate 210. Yet still, the wavelength maybe chosen to affect support substrate 210. For example, in anembodiment, a specific wavelength of light may be chosen to adhereproduct substrate 248 to support substrate 210.

The focus area of energy-emitting device 236 (indicated by the dashedlines emanating vertically from energy-emitting device 236 in FIG. 2Btoward product substrate 248) may be sized according to the size of theLED, such as for example, a 300 micron wide area.

In addition, as discussed in more detail with respect to FIG. 4, supportsubstrate 210 may have a plurality of holes that permit energy of theenergy-emitting device 236 to physically pass therethrough, withoutbeing absorbed or contacting support substrate 210, such that the energyof energy-emitting device 236 directly reaches product substrate 248.

In an embodiment using a laser, upon actuation of a predeterminedcontrolled pulse duration of laser 236, circuit trace 212 may begin tocure (and/or melt or soften) to an extent that a fusing bond may formbetween the material of circuit trace 212 and the electrical contactterminals (not shown) on die 220. In addition, as mentioned previously,a further bond may form between die 220 and product substrate 248,either during the same or additional pulses of the laser used to affixdie 220. This further bond may assist in separating die 220 from wafertape 218, as well as simultaneously affixing die 220 to circuit trace212 and/or product substrate 248. These bonds may be modified and/orcontrolled through a different selection of material of circuit trace212, die 220, material of product substrate 248, and/or a particularwavelength of light emitted by a laser as the energy-emitting device236. Additionally, energy-emitting device 236 may cause some heattransfer on wafer tape 218, thereby reducing adhesion of die 220 towafer tape 218 and thus assisting in the transfer operation.

In other instances, die may be released and fixed to the productsubstrate in many ways, including using a laser having a predeterminedwavelength or a focused light (e.g., IR, UV, broadband/multi spectral)for heating/activating circuit traces to thereby cure an epoxy or phasechange bond materials, or for deactivating/releasing a die from wafertape, or for initiating some combination of reactions. Furthermore, avacuum may be implemented to pull a die from the wafer tape, and/or airpressure may be implemented to push the die onto a product substrate,potentially including a rotary head between the die wafer substrate andthe product substrate. In yet another instance, ultrasonic vibration maybe used to cause the die to bond to the circuit traces.

Similar to needle retraction support 230, fixing mechanism 208 may alsoinclude a substrate support 238, which may be disposed betweenenergy-emitting device 236 and a bottom surface of support substrate210. Support 238 may include an opening 240 at a base end thereof and anopening 242 at an upper end thereof. For instance, support 238 may beformed as a ring or hollow cylinder. Energy-emitting device 236 emitsthe energy through openings 240, 242 to reach product substrate 248.Support 238 may also include a structure to secure a lens (not shown) toassist in directing the emitted energy from energy-emitting device 236toward product substrate 248.

Furthermore, the upper end of the sidewalls of support 238 may bedisposed in direct contact with or closely adjacent to the bottomsurface of support substrate 210. Positioned as such, support 238 mayhelp to prevent damage from occurring to support substrate 210 and/orproduct substrate 248 during the stroke of needle 226 at or during thetime of a transfer operation. In addition, similar to support 230,support 238 may prevent deformation of support substrate 210 and/orproduct substrate 248 so as to assist in accurate placement of diecorresponding to a preconfigured layout (die map data).

In some instances, during the transfer operation, the portion of thebottom surface of support substrate 210 aligned with support 238 maycontact support 238, which thereby provides resistance against theincoming motion of die 220 being pressed by needle 226. Moreover,support 238 may be movable in a direction of the vertical axis to beable to adjust a height thereof so as to raise and lower support 238 asnecessary, including to a height of support substrate 210.

In addition to the above features, apparatus 200(1) may further includea first sensor 244, from which apparatus 200(1) receives informationregarding die 220 on wafer tape 218. In order to determine which die isto be used in the transfer operation, wafer tape 218 may have a bar code(not shown) or other identifier, which is read or otherwise detected.The identifier may provide die map data to apparatus 200(1) via firstsensor 244.

As shown in FIGS. 2A and 2B, first sensor 244 may be positioned neartransfer mechanism 206 (or needle 226, specifically), spaced apart fromtransfer mechanism 206 by a distance (d), which, in some instances, mayrange from about 1-5 inches, so as to enhance the accuracy of locationdetection. In an alternative embodiment, first sensor 244 may bedisposed adjacent the tip of needle 226 in order to sense the exactposition of die 220 in real time. It is also contemplated that duringthe transfer operation or over the course of the operation, wafer tape218 may be punctured and or stretched, which may alter the previouslymapped, and thus expected, locations of die 220 on wafer tape 218. Assuch, small changes in the stretching of wafer tape 218 could add up tosignificant errors in alignment of die 220 being transferred. Thus, realtime sensing may be implemented to assist in accurate die location.

In some instances, first sensor 244 may be able to identify the preciselocation and type of die 220 being sensed. This information may be usedto provide instructions to wafer tape conveyor frame 222 indicating theexact location to which wafer tape 218 should be conveyed in order toperform the transfer operation. Sensor 244 may be one of many types ofsensors, or a combination of sensor types to better perform multiplefunctions. For instance, sensor 244 may include, but is not limited to:a laser range finder or an optical sensor, such as a non-limitingexample of a high-definition optical camera having micro photographycapabilities.

Moreover, in some instances, a second sensor 246 may also be included inapparatus 200(1). Second sensor 246 may be disposed with respect tosupport substrate 210 or product substrate 248 so as to detect theprecise position of circuit trace 212 on product substrate 248. Thisinformation may then be used to determine any positional adjustmentneeded to align product substrate 248 between transfer mechanism 206 andfixing mechanism 208 so that the next transfer operation occurs in thecorrect location on circuit trace 212. This information may further berelayed to apparatus 200(1) to coordinate conveying product substrate248 to a correct position, while simultaneously conveying instructionsto wafer tape conveyor frame 222. A variety of sensors are alsocontemplated for sensor 246 including optical sensors, such as onenon-limiting example of a high-definition optical camera having microphotography capabilities.

FIGS. 2A and 2B further illustrate that first sensor 244, second sensor246, and energy-emitting device 236 may be grounded. In some instances,first sensor 244, second sensor 246, and energy-emitting device 236 mayall be grounded to the same ground (G), or alternatively, to a differentground (G).

Depending on the type of sensor used for first and second sensors 244,246, first or second sensors 244, 246 may further be configured to testthe functionality of transferred die. Alternatively, an additionaltester sensor (not shown) may be incorporated into the structure ofapparatus 200(1) to test individual die before removing productsubstrate 248 from apparatus 200(1).

After transferring die(s) 220, product substrate 248 may be removed fromapparatus 200(1) and/or support substrate 210. Thereafter, productsubstrate 248 may undergo additional processing or may be incorporatedinto a product circuit.

Furthermore, in an embodiment, multiple independently-actuatable needlesand/or lasers may be implemented in a machine to transfer and fixmultiple die at a given time. The multiple needles and/or lasers may beindependently movable within a three-dimensional space. Multiple dietransfers may be done synchronously (multiple needles going down at thesame time), or concurrently but not necessarily synchronously (e.g., oneneedle going down while the other is going up, which arrangement maybalance better the components and minimize vibration). Control of themultiple needles and/or lasers may be coordinated to avoid collisionsbetween the plurality of components. Moreover, in other examples, themultiple needles and/or lasers may be arranged in fixed positionsrelative to each other.

Second Example Embodiment of a Direct Transfer Apparatus

In an additional embodiment of a direct transfer apparatus of FIGS. 2Aand 2B, as seen in FIG. 2C, apparatus 200(2) may include a wafer tapeconveyance mechanism 250. In particular, in lieu of wafer tape conveyorframe 222 and tensioner frame 224 shown in FIGS. 2A and 2B, wafer tapeconveyance mechanism 250 may include a system of one or more reels 252to convey die 220 through the transfer position of apparatus 200(2) totransfer die to a substrate. In particular, each reel 252 may include asubstrate 254 formed as a narrow, continuous, elongated strip having die220 attached consecutively along the length of the strip.

In the case where a single reel 252 is used, a transfer operation mayinclude conveying product substrate 248, via support substrateconveyance mechanism 202 as described above, using motors, tracks, andgears. However, wafer tape conveyance mechanism 250 may include asubstantially static mechanism, in that, while die 220 may be fedcontinuously through the transfer position by unrolling substrate 254from reel 252, reel 252 itself main remain in a fixed position. In someinstances, the tension of substrate 254 may be maintained for stabilitypurposes by tensioning rollers 256, and/or a tensioning reel 258, whichmay be disposed on a side of apparatus 200(2) opposite reel 252.Tensioning reel 258 may roll up substrate 254 after die 220 have beentransferred to product substrate 248. Alternatively, the tension may bemaintained by any other suitable means to secure substrate 254 so as toassist in pulling it through the transfer position after each transferoperation to cycle through die 220.

In an embodiment where multiple reels 252 are used, each reel 252 may bedisposed laterally adjacent to other reels 252. Each reel 252 may bepaired with a specific transfer mechanism 206 and a specific fixingmechanism 208. In this case, each respective set of transfer mechanismsand fixing mechanisms may be arranged with respect to product substrate248 such that multiple die may be placed in multiple locations on thesame product substrate 248 simultaneously. For instance, in someinstances, the respective transfer positions (i.e., the alignmentbetween a transfer mechanism and a corresponding fixing mechanism) maybe in a line, offset, or staggered so as to accommodate various circuittrace patterns. Note that in an embodiment with a plurality of reels252, a circuit trace pattern may be such that not every transfermechanism may need to be actuated simultaneously. Accordingly, multipletransfer mechanisms may be actuated intermittently as the productsubstrate is conveyed to various positions for transfer.

Whether one reel 252 or a plurality of reels 252 are implemented, thedie transfer operation may be relatively similar to the transferoperation as described above with respect to the first exampleembodiment of the direct transfer apparatus 200(1) in FIGS. 2A and 2B.For instance, product substrate 248 may be conveyed to a transferposition (die fixing position) in the same manner as described above viasupport substrate conveyance mechanism 202, transfer mechanism(s) 206may perform a needle stroke to transfer die 220 from die substrate 254to product substrate 248, and fixing mechanism 208 may be actuated toassist in affixing die 220 to product substrate 248.

Example Product Substrate

FIG. 3 illustrates an example embodiment of a processed productsubstrate 300. A product substrate 302 may include a first portion of acircuit trace 304A, which may perform as a negative or positive powerterminal when power is applied thereto. A second portion of circuittrace 304B may extend adjacent to first portion of circuit trace 304A,and may act as a corresponding positive or negative power terminal whenpower is applied thereto.

As similarly described above with respect to the wafer tape, todetermine where to convey product substrate 302 to perform the transferoperation, product substrate 302 may have a bar code (not shown) orother identifier, which is read or otherwise detected. The identifiermay provide circuit trace data to the apparatus, for instance, apparatus200(1).

Product substrate 302 may further include datum points 306 that act asvisual indicators for sensing by the product substrate sensor (forexample, second sensor 246 in FIG. 2) to locate the first and secondportions of circuit trace 304A, 304B. Once datum points 306 are sensed,a shape and relative position of the first and second portions ofcircuit trace 304A, 304B with respect to datum points 306 may bedetermined based on preprogrammed information. Using the sensedinformation in connection with the preprogrammed information, supportsubstrate conveyance mechanism 202 may convey product substrate 302, viasupport substrate 210, to the proper alignment position for the transferoperation.

Additionally, die 308 are depicted in FIG. 3 as straddling between thefirst and second portions of circuit trace 304A, 304B. In this manner,the electrical contact terminals (not shown) of die 308 may be bonded toproduct substrate 302 during a transfer operation. Accordingly, powermay be applied to run between the first and second portions of circuittrace 304A, 304B, thereby powering die 308. For example, the die may beunpackaged LEDs that were directly transferred from a wafer tape to thecircuit trace on product substrate 302. Thereafter, product substrate302 may be processed for completion of product substrate 302 and used ina circuit or other final product. Further, other components of a circuitmay be added by the same or other means of transfer to create a completecircuit, and may include control logic to control LEDs as one or moregroups in some static or programmable or adaptable fashion.

Example of a Support Substrate

FIG. 4 illustrates a support substrate 400 used during the transfer ofdie 220 onto product substrate 248. Support substrate 400 is configuredaccording to a custom configuration prior to transferring die to aproduct substrate. Note, the depiction of product substrate 248 asseparated (i.e. not attached) from support substrate 402 is shown forpurposes of discussion of the features of FIG. 4. However, it isunderstood that during the process of transferring die 220, supportsubstrate 210 physically supports product substrate 248.

In an embodiment as depicted, support substrate 402 may have a pluralityof holes 404. While holes 404 are shown at certain locations,corresponding to a particular configuration, it is contemplated that theholes 404 may be arranged in any manner to correspond to a placement ofdie 220 on product substrate 248 (via a die data map).

As indicated above, the plurality of holes 404 may be located in supportsubstrate 402 to align with a respective portion of product substrate248 and/or circuit trace 212 (not shown) where die 220 are to be placed.Energy from energy-emitting device 236 may affect area 406 and conditionproduct substrate 248 and/or circuit trace 212 to receive a die 220.Thus, holes 404 are positioned to allow energy from energy-emittingdevice 236 (not shown) to pass therethrough and directly reachrespective portions of product substrate 248 to assist in transferringdie 220 onto product substrate 248. Note that holes in the supportsubstrate do not significantly affect the integrity of the supportsubstrate or the ability to adequately support a product substrate.

Furthermore, while FIG. 4 illustrates support substrate 402 having holes404, consistent with the previous description of the flexible supportsubstrate, the support substrate may have a continuous surface, andtherefore, have no holes. In such an embodiment, and as discussed, theenergy from the energy-emitting device may pass through the material ofthe support substrate and affect the corresponding portion of productsubstrate 248 as indicated by area 406 and/or the circuit trace to affixdie to the product substrate.

Another Example of a Support Substrate

FIG. 5 illustrates a perspective view 500 of an embodiment of a productsubstrate 502 and a support substrate 504. The depiction of productsubstrate 502 as being separated from support substrate 504 is shown forpurposes of discussion of the features of FIG. 5. Accordingly, duringthe process of transferring die 220, product substrate 502 and supportsubstrate 504 are in contact.

As mentioned above, product substrate 502 may include one or moreprotrusions 506 that extend from a lower surface of product substrate502. In an embodiment, a user may determine which product substrate 502is involved in the transfer process and select a support substrate 504that includes holes 508 arranged within support substrate 504 thatcorrespond in pattern/location to the pattern/location of protrusions506 on product substrate 502. Protrusions 506 may then be aligned withholes 508 to secure product substrate 502 to support substrate 504during the transfer process.

While protrusions 506, and their corresponding holes 508, are shown as aparticular shape, any shape may be used (e.g. square, hexagonal, etc.).In addition, any pattern or configuration of protrusions 506 and holes508 may be implemented. Furthermore, protrusions 506 may be longer than,equal to, or shorter than a thickness dimension of support substrate504. Alternatively, in an embodiment (not shown), the system ofprotrusions 506 and holes 508 may be switched such that the protrusionsare located on the support substrate and the corresponding holes arelocated on the product substrate.

Example Direct Transfer Method

A method 600 of executing a direct transfer process, in which one ormore die is directly transferred from a wafer tape to a productsubstrate, is illustrated in FIG. 6. The steps of method 600 describedherein may not be in any particular order, and as such, may be executedin any satisfactory order to achieve a desired product state or ultimatecircuitry.

Method 600 may include a step of loading transfer process data into a PCand/or a data store 602. The transfer process data may include data suchas die map data, circuit CAD files data, and needle data. A step ofloading a wafer tape into a wafer tape conveyor mechanism may also beincluded in method 600. Loading the wafer tape into the wafer tapeconveyor mechanism may include controlling the wafer tape conveyormechanism to move to a load position, which is also known as an extractposition. The wafer tape may accordingly be secured in the wafer tapeconveyor mechanism in the load position.

The wafer tape may be loaded so that the die are facing downward towardthe product substrate, which may be located within the support substrateconveyor mechanism so as to be positioned on the support substrate. Theproduct substrate may be loaded such that the circuit trace faces towardthe die on the wafer. In some instances, the product substrate may bepositioned on the support substrate before the support substrate isplaced into the support substrate conveyance mechanism.

Method 600 may further include a step of preparing the product substrateto be placed onto the support substrate. Preparing the product substratemay include securing the product substrate to the support substrate suchthat the product substrate does not reposition while transferring die(s)to product substrate. In addition, preparing the product substrate mayinclude a step of printing a circuit trace on the product substrateaccording to the pattern of the CAD files being loaded into the PC ordata store. Similarly, datum points may be printed onto the circuitsubstrate in order to assist in the transfer process.

To place die, the support substrate conveyor mechanism may be controlledto move to a load position, which is also known as an extractionposition, whereat the support substrate may be loaded into the supportsubstrate conveyor mechanism. In some instances, the product substratemay be delivered and placed in the load position by a conveyor (notshown) or other automated mechanism, such as in the style of an assemblyline. Alternatively, the product substrate may be manually loaded andapplied to the support substrate by an operator.

Once the product substrate is properly loaded within the supportsubstrate conveyor mechanism and the wafer tape is properly loaded intothe wafer tape conveyor mechanism, a program to control the directtransfer of the die from the wafer tape to the circuit trace of theproduct substrate may be executed via the PC to commence the directtransfer operation 608.

CONCLUSION

Although several embodiments have been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the claims are not necessarily limited to the specific features oracts described. Rather, the specific features and acts are disclosed asillustrative forms of implementing the claimed subject matter.Furthermore, the use of the term “may” herein is used to indicate thepossibility of certain features being used in one or more variousembodiments, but not necessarily in all embodiments.

What is claimed is:
 1. An apparatus for transferring a semiconductor diefrom a wafer tape to a product substrate, the apparatus comprising: awafer frame configured to secure the wafer tape; a support frameconfigured to secure a support substrate having a plurality of holes,the support substrate configured to secure the product substrate; and anactuator configured to transfer the semiconductor die to a transferlocation on the product substrate.
 2. The apparatus according to claim1, further comprising a controller communicatively coupled to the waferframe and the support frame, the controller including memory havinginstructions, which when executed, cause the controller to performoperations comprising: orienting the wafer frame such that thesemiconductor die is aligned with the transfer location, orienting thesupport frame such that the product substrate is aligned with thetransfer location, and causing the actuator to transfer thesemiconductor die at the transfer location.
 3. The apparatus accordingto claim 1, further comprising: a first sensor configured to sense alocation of the semiconductor die with respect to the transfer location;and a second sensor configured to sense a location of the productsubstrate with respect to the transfer location.
 4. The apparatusaccording to claim 1, wherein at least one hole of the plurality ofholes aligns with the transfer location.
 5. The apparatus according toclaim 1, wherein the plurality of holes is a first plurality of holes,wherein the support substrate includes a second plurality of holes,wherein the product substrate includes a plurality of protrusions, andwherein the product substrate is securable to the support substrate viathe plurality of protrusions aligning with respective holes of thesecond plurality of holes.
 6. The apparatus according to claim 1,wherein the support substrate further includes a plurality ofprotrusions, wherein the product substrate includes a plurality ofholes, and wherein the product substrate is securable to the supportsubstrate via the plurality of holes in the product substrate aligningwith respective protrusions of the plurality of protrusions on thesupport substrate.
 7. The apparatus according to claim 1, wherein theproduct substrate includes a plurality of protrusions, and wherein oneor more protrusions of the plurality of protrusions on the productsubstrate are configured to align with one or more holes, respectively,of the plurality of holes in the support substrate.
 8. The apparatusaccording to claim 1, wherein the actuator is configured to transfer,simultaneously, a plurality of semiconductor die to respective transferlocations on the product substrate.
 9. An apparatus to affixsemiconductor die to respective transfer locations on a productsubstrate, the apparatus comprising: a support substrate frame to securea support substrate, the support substrate having a plurality of holescorresponding to the respective transfer locations of the semiconductordie on the product substrate, the product substrate being securable tothe support substrate; a die substrate frame to secure a die substrateincluding the semiconductor die thereon; and a die separation device toseparate the semiconductor die from the die substrate and transfer thesemiconductor die to the respective transfer locations of thesemiconductor die on the product substrate.
 10. The apparatus accordingto claim 9, wherein the die separation device affixes the semiconductordie to a circuit trace on the product substrate.
 11. The apparatusaccording to claim 9, wherein the die separation device is configured totransfer at least two semiconductor die to the product substrate duringa single actuation of the die separation device.
 12. The apparatusaccording to claim 9, wherein the die substrate frame and the supportsubstrate frame are movable independently of each other andsimultaneously.
 13. The apparatus according to claim 9, wherein one ormore material characteristics of the support substrate is based at leastin part on one or more structural characteristics of the semiconductordie.
 14. The apparatus according to claim 9, wherein the productsubstrate includes at least one protrusion, and wherein the at least oneprotrusion aligns with at least one hole of the plurality of holes inthe support substrate when secured thereto.
 15. The apparatus accordingto claim 9, wherein the product substrate is removably attached to thesupport substrate.